This application pertains to the art of sandblasting and, more particularly, to self-contained sandblasting apparatus of the type wherein a large sand supply receptacle, an air compressor and pneumatically operated sandblasting devices are all mounted on a common wheeled support and transport platform.
Large sandblasting projects, such as sandblasting large buildings or a plurality of storage tanks for petroleum products, frequently take many days or weeks to complete. Pneumatically operated sandblasting devices normally have sand reservoirs which do not hold more than around 2000 pounds of sand. Such reservoirs must be refilled rather frequently, and this requires extra labor and equipment, along with lost time.
Many arrangements have been proposed for arranging the various equipment required for sandblasting operations so that frequent replenishing of the sand is not required or is easily accomplished. U.S. Pat. No. 3,498,003 issued Mar. 3, 1970, to Hulbert discloses an arrangement wherein a sandblasting device, an air compressor and a sand supply receptacle are all separate from one another. This makes it difficult to transport the equipment to a work site and is further difficult to transport the equipment from one location to another at the work site. In addition, the sandblasting device must be of the type which requires a vacuum transfer of sand from the supply receptacle to the reservoir on the sandblasting device.
U.S. Pat. No. 3,399,492 issued Sept. 3, 1968, to Crowe, et al. discloses an arrangement wherein a sand supply receptacle and sandblasting devices are mounted on a wheeled support and transport platform. However, the air compressor is towed as a separate piece of equipment. In addition, the sand supply receptacle requires a sloping bottom in order to insure complete discharge of its contents into the reservoir on the sandblasting device. The use of a receptacle with a sloping bottom greatly reduces the capacity of the receptacle, and a great deal of space is wasted. The sandblasting devices in Crowe also are rather permanently mounted to the platform so that replacement and repair, or adjustment, would be rather difficult. A pneumatic transfer conveyor is also required for transferring sand to the relatively small sand receptacle from a tank car.
U.S. Pat. Nos. 3,075,319 issued Jan. 29, 1963, to Blubaugh and 3,559,343 issued Feb. 2, 1971, to Foster disclose apparatus wherein a sand supply receptacle, an air compressor and sandblasting devices are all mounted on a common support and transport platform. The Blubaugh apparatus has a sand supply receptacle with a steeply sloping bottom and this wastes a large amount of space on the apparatus. In order to obtain a large capacity in the sand supply receptacle, the receptacle would have to be extremely high. In addition, the sandblasting devices are mounted forwardly of the sand supply receptacle in a relatively inaccessible and permanent manner so that replacement and repair thereof would be somewhat difficult. Furthermore, there is no provision in Blubaugh for raising the sandblasting devices for road clearance during transport, with the only adjustment being for the outlet nozzles. The Foster apparatus includes a relatively small sand supply bin in the embodiment of FIGS. 6 and 7, and a workman must frequently replenish such bin by emptying bags of sand into the same. The pneumatically operated sandblasting device is positioned on the support and transport platform itself so it would not be possible to conveniently replenish a sand reservoir on the sandblasting device by gravity flow from a large receptacle mounted on the platform.